in tetrahydrofuran heating overnight; hot filtration, crystn. at room temp.;

in tetrahydrofuran Ar-atmosphere; room temp., 15 h; partial evapn. of solvent; cooling (-30°C; pptn.); filtration; drying (vac.);

tetrahydrofuran in tetrahydrofuran Soxhlet extn. of solid trichloride with refluxing THF;

K[BEt3H] in tetrahydrofuran byproducts: KCl; under Ar, Schlenk technique; soln. of K(BEt3H) (80 mmol) added dropwise to suspn. of VCl3*3THF (20 mmol) (room temp., 2 h); stirred (2 h, room temp.); KCl filtered off; solvent removed (vac.); solid dissolved in fresh THF; added to suspn. of SiO2 in THF; stirred (8 h); dried (vac., 24 h);

in tetrahydrofuran; diethyl ether -10°C, after treatment of the mixt. with pyridine;

phenyl-magnesium bromide in tetrahydrofuran addn. of the V complex to PhMgBr in THF at -15°C; addn. of oxygen-free H2O; filtration; evapn.; (C6H5)2 sublimated off; extn. of the residue with hexane/ether (3:1); from the mixt. of (C6H6)2V and (C6H5C6H5)2V, (C6H6)2V is isolated by recrystn. from ether at -20°C;